This invention relates generally to a typewriter and more particularly to a novel and improved justifying typewriter capable of preparing automatically a justified line printout comparable in uniformity and aesthetic value to that of conventional typesetting apparatus.
The hard copy printout of a conventional typewriter is lacking in quality when compared to the typesetting process. The conventional typewriter has fixed escapement to establish the same horizontal space for all characters. This invention provides for automatic variable escapement adjusting the spacing for different width characters and provides automatic justificaton of right and left margins by automatic calculation of spaces between words. The printout of the conventional typewriter is less economical than the typesetting process in that it does not efficiently utilize the full space available on the printout sheet. A number of conventional mechanical and electric typewriters have the printout sheet advanced by the carriage relative to the type bar which impacts the sheet; and more recently, other typewriters have utilized a single element spherical printing head, such as, that employed in the Model 745 IBM Selectric typewriter. In this form the printing head is moved relative to the sheet as it prints. Broadly, a preferred embodiment of the present invention utilizes a Model 745 IBM Selectric typewriter which is modified to operate as a typographical machine to produce a typewritten printout comparable to that set by a typographer and is characterized by automatically regulating the spacing between characters, words and justified lines in a continuous printout.
Accordingly, it is a general object of the present invention to provide a novel and improved form of an automatic justifying typewriter capable of producing a high quality printout utilizing the printing apparatus of a conventional typewriter.
Another object of this invention is to provide a novel and improved form of an automatic justifying typewriter which may be readily set up for printing out different type sizes, styles and weights of characters.
Yet a further object of this invention is to provide a novel automatic justifying typewriter capable of having the printing information input from a conventional typewriter keyboard which utilizes a computer to prearrange the characters for a proportionally spaced, justified line printout.
Still a further object of this invention is to provide a novel automatic justifying typewriter having a range of horizontal space settings coordinated with the various type fonts and utilizing first incremental drive means for the carriage as well as incremental drive means for positioning the printout sheet in the proper position relative to the character printing means.
A further object of this invention is to provide a novel automatic justifying typewriter capable of on-line operation with a computer or other memory or data source.
Yet a further object of the present invention is to provide a novel automatic justifying typewriter characterized by having incremental drive means operatively associated with the printer for effecting relative horizontal and vertical movement between the character printing means and the printout sheet, the actuation of the printer and incremental drive means being controlled by coded printing control signals and spacing control signals from a data source which automatically regulates the spacing between characters, words and lines according to preassigned values.
In accordance with the present invention, in a preferred form there is provided a keyboard printer conventionally of the type having a single element print head on a horizontally movable carriage and a printout sheet selectively engaged by the printing head. Incremental drive means are defined by a horizontal stepping motor coupled to the carriage and a vertical stepping motor coupled to the platen. A computer serves as a data source which is programmed to generate coded signals for controlling both the printing operations and motor stepping operations so that after each printing operation there is a spacing operation and, after each character is printed, the horizontal stepping motor advances the carriage a preselected horizontal distance called pitch proportional to the width of that character before the next character is printed. After each line is printed the vertical stepping motor is caused to rotate or index the platen through a variable preselected angle of rotation. Logic circuits are used to selectively actuate the printer, horizontal stepping motor and vertical stepping motor in the proper sequence. Most desirably, a gear shift mechanism is associated with the horizontal stepping motor to facilitate pitch adjustment of the horizontal space increment for a particular type font.
Other objects, advantages and capabilities of the present invention will become more apparent as the description proceeds taken in conjunction with the accompanying drawings.